Quantitative fatty acid signature analysis (QFASA) is widely used to investigate trophic interactions in marine ecosystems, as nutritionally important ω 3 long-chain polyunsaturated fatty acids at the food web base allow tracing of their trophic transfer in the food chain. By contrast, the basal resources in soil food webs comprise a wider array of trophic markers, including branched-chain, cyclopropane as well as several mono- and polyunsaturated fatty acids. These diverse markers allow distinguishing between the three dominant soil carbon and energy channels, the root, bacterial and fungal pathway. QFASA has not been applied yet to soil ecosystems owing to the lack of a priori data to fit the model. The present work investigates the transfer of absolute and relative trophic marker fatty acids into Collembola as dominant representatives of the soil mesofauna. Three different species were fed on a variety of single diets characteristic for the green and brown food chain. Calibration coefficients were calculated and diet estimation trials for mixed diet set-ups were performed, using a library comprising 50 different resources. However, estimation of Collembola diet was only partially successful, identifying the main components, but not the correct relative proportions. Adjustments by fat content or diet group exclusion did not improve the results. Nonetheless, this work provides, to our knowledge, a first comprehensive dataset to translate the application of QFASA from marine to soil ecosystems. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

中文翻译：

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转移系统：在土壤食物网中应用定量脂肪酸特征分析的先决条件

定量脂肪酸特征分析 (QFASA) 广泛用于研究海洋生态系统中的营养相互作用，因为它具有重要的营养价值ω食物网底部的 3 种长链多不饱和脂肪酸可以追踪它们在食物链中的营养转移。相比之下，土壤食物网中的基础资源包含更广泛的营养标记，包括支链、环丙烷以及几种单不饱和脂肪酸和多不饱和脂肪酸。这些不同的标记可以区分三种主要的土壤碳和能量通道：根、细菌和真菌途径。由于缺乏相关资料，QFASA 尚未应用于土壤生态系统。先验数据来拟合模型。目前的工作研究了绝对和相对营养标记脂肪酸向作为土壤中底动物的主要代表的跳虫的转移。三种不同的物种以绿色和棕色食物链特有的各种单一饮食为食。使用包含 50 种不同资源的库计算校准系数并进行混合饮食设置的饮食估计试验。然而，对弹尾虫饮食的估计仅部分成功，确定了主要成分，但没有正确的相对比例。通过脂肪含量或饮食组排除进行调整并没有改善结果。尽管如此，据我们所知，这项工作提供了第一个全面的数据集，将 QFASA 的应用从海洋生态系统转化为土壤生态系统。本文是主题“脂质作为‘营养生物标志物’的下一个前景：消费者改变膳食脂肪酸的证据和意义”的一部分。